TWI593331B - Device and method for detaching protective foils - Google Patents

Description

Device and method for peeling protective film

The present invention relates to an apparatus and method for peeling a protective film from a printed circuit board.

Printed circuit boards (also known as Leiterkarte, Platine or gedruckte Schaltung; printed circuit boards in English) are the carriers of electronic components. Its role lies in mechanical fixation and electrical connection. The printed circuit board consists of an electrically insulating material and an electrically conductive connection (printed wire) attached thereto. Insulating materials are generally made of fiber reinforced plastic.

The prior art fully automatic double-sided lamination of a photopolymer layer having a protective film on a copper clad printed circuit board substrate by a so-called Cut-Sheet-Laminator. A cut photopolymer layer having a protective film at a distance from the edge is overlaid on the copper clad printed circuit board substrate. The film preferably has a margin between 0.5 mm and 3 mm. However, the protective film must be removed from the printed circuit board again during the processing procedure.

The existing fully automatic device can laminate the photopolymer layer with the protective film and can remove the protective film again. However, good film removal is never achieved. In the case where the printed circuit board substrate (thickness not exceeding 12.5 μm) and the copper clad layer (thickness of about 9 μm, part of the copper thickness is at most several μm) are getting thinner and thinner, after the exposure process It is more difficult to peel off the protective film from the photopolymer layer. During this process, the copper clad printed circuit board substrate may be damaged by, for example, bending.

In addition, such lamination-exposure-peel-developing and stripping procedures are carried out in automated equipment having a line speed of up to 9 m/min. To date, conventional devices have not achieved good membrane separation at such high speeds.

EP 215 397 B1 discloses a device for peeling off a protective film from a copper clad printed circuit board substrate. It is a device for peeling off a film attached to a plate body, wherein a pressure member applies pressure to a front surface of a film attached to the plate member and a film is peeled from the plate body by a liquid ejecting device in this region.

US 20140076501 A1 discloses an apparatus for stripping a film from a substrate. For this purpose, the device has a transport module for transporting the substrate and a stripping module. For example, an OLED display having a protective film on both sides is provided.

DE 42 21 703 C2 discloses a method and a device for stripping a protective film on a single or double side from a copper clad printed circuit board. A protective film is attached to the printed circuit board, wherein the protective film is first peeled off at the edge of the printed circuit board by a blowing unit composed of a hollow needle and jetted to lift the protective film. In the process of continuing to advance the printed circuit board, the protective film is lifted to the plate-shaped guide fins at an acute angle along the needle back of the hollow needle and sent to the coil by the transport mechanism. The protective film is thermally connected to the previously peeled protective film, wherein a plate-shaped guide fin for guiding the printed circuit board is provided in this region. The guide fins are separated by a certain distance, even if the curved printed circuit board can pass through the gap between the guide fins in the direction of the program flow.

WO2011035932A2 describes an apparatus and method, in particular for separating membranes from printed circuit boards. The device has a plate body with discrete edges that are partially wedge-shaped and can be embedded between the printed circuit board and the film. The outlet tip has an outlet point. The film is separated from the printed circuit board in the separated side region by blowing in air.

None of the above conventional devices and methods are capable of separating the protective film from the extremely thin printed circuit board substrate on which the polymer layer is laminated without impairing the printed circuit board. Printed circuit boards are bent in most cases.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an apparatus and method for separating a protective film from an extremely thin copper-clad printed circuit board substrate at a relatively high line speed without damaging the printed circuit board substrate.

The main feature is that at least one supplemental air nozzle is provided in the feed zone of the stripping unit, the supplemental air nozzle loading the drum with an air flow and attaching the released portion of the protective film along the roller.

The present invention is characterized in that, as a first step of sucking the separated end of the protective film, a vacuum aspirator provided in the drum is not used, but a weaker suction effect is employed.

The prior art does not treat this as the prior art always uses a suction nozzle with a strong suction function.

The disadvantage is that the vacuum aspirator provided in the drum can suck the separated end of the protective film and keep it at the periphery of the drum, but at the same time, the suction air flow is strongly and undesirably sucked up and printed together. The board causes the printed circuit board to bend or otherwise be severely damaged.

According to the present invention, the starting point of the separated end of the protective film is not sucked by the suction nozzle, but is attached to the outer circumference of the drum through the Coanda effect, and then rotated by a certain angle with the drum until the nozzle provided in the drum intercepts The ends are separated and transported away.

Thereby ensuring that the separated end of the protective film is initially transmitted through the weak pump The suction effect is attached to the outer circumference of the drum, and a stronger suction effect is generated by the suction nozzle at a later time. At this time, the suction nozzle is separated from the printed circuit board by a sufficient distance, and the printed circuit board can no longer be damaged when it functions.

According to a first embodiment of the invention, the supplemental air nozzle which produces a weaker suction effect in accordance with the Coanda principle is provided upstream of the drum to form a tangential air flow over the outer circumference of the drum. According to a second embodiment, the supplemental air nozzle is integrated in the drum, in particular in the slot region formed there. If the supplementary air nozzle is described singular in the following, this description is not restrictive since several supplementary air nozzles may be provided in parallel in actual operation.

According to the first preferred embodiment, air is blown tangentially along the slots of the upper and/or lower rollers, and the air separates the protective film which has been slightly peeled off from the intermediate portion from the printed circuit board. The peeled film is gently separated from the pliable thin printed circuit board by the rotation of the drum and by holding the protective film on the surface of the drum.

The apparatus of the present invention utilizes the Coanda effect, which is characterized in that Coanda-Strömung flows along the convex wall without departing from the surface. Therefore, the generated air jet flows along the convex cylinder of the drum. The air flow thus formed causes the protective film to adhere to the cylinder surface and rotates with the drum. Thereby, a negative pressure is formed in the groove region, and the protective film adheres to the drum surface almost 360° under the action of the negative pressure.

To this end, preferably the device has so-called up and down (supplement) air nozzles in the slot region of the drum which hold the released portion of the protective film along the surface of the drum. This gentle membrane retention is achieved by the Coanda effect (or Bernoulli effect or hydrodynamic enthalpy). The gas jet produced by the supplemental air nozzle is a spatially narrow stream that is distinctly different from the (mostly stationary) surrounding environment.

Preferably, vacuum suction is initiated after successful separation of the membrane from the printed circuit board The vacuum aspirator continues to hold the membrane to the surface of the drum. The air nozzle is cut off after successful transfer.

The protective film is preferably held by the apparatus of the present invention when the drum is rotated 90° and then transferred to the integrated vacuum aspirator.

According to a preferred embodiment, the stripping device has a single rotating drum with a supplemental air slot. This embodiment is for separating a film on one side of a printed circuit board substrate.

However, the invention is not limited to providing a rotating drum. The present invention can also be provided with a plurality of rotating drums including supplemental air slots.

According to another preferred embodiment, the stripping device has two rotating drums spaced apart in a vertical direction. In this embodiment, the printed circuit board substrate is passed between the rotating rollers to complete the separation process of the two films of the top and bottom surfaces of the printed circuit board substrate.

It is beneficial to first transport the lower protective film into the receiving container. The upper drum is rotated 360°, wherein the film is transferred from the upper drum to the lower drum in the contact zone of the upper and lower drums. The film is then placed in the receiving container by the lower roller. The main advantage is that only one receiving container needs to be set, which has a beneficial effect on the necessary space requirements.

Preferably, the vacuum aspirator is cut off when the film is transferred to the lower drum, so that the protective film is detached from the surface of the drum and falls into the receiving container. Additionally or alternatively, the separation of the membranes can also be achieved by the slight application of compressed air and/or by mechanical peeling device elements.

Since all protective membranes are stored in a common receiving container below the protective film stripping device, only a small air turbulence is formed, so that such equipment can also be operated in a clean room.

According to another preferred embodiment, the protective film peeling device of the present invention can be fully automated on a production line. The reason for this is that the apparatus of the present invention achieves an extremely high error-free separation rate.

In addition, the protective film peeling device is extremely compact and space-saving. The main advantage is that the device can be integrated into the production line including the exposure machine, the stripper and the developing module with as short a line length as possible.

The object of the invention is to include not only the purpose of the individual claims but also the combination of individual claims.

All the information and features disclosed in the document (including the abstract of the invention), especially the spatial construction shown in the drawings, should be considered as innovations of the present invention, whether individually or in combination with the novelty of the prior art. point.

The invention is explained in detail below with reference to the drawings and several embodiments thereof shown. The features and advantages of other constituent innovations of the present invention are included in the drawings and the associated description.

1‧‧‧ peeling device

2‧‧‧Printed circuit board substrate

3‧‧‧Uplighting polymer layer

4‧‧‧ Lower photopolymer layer

5‧‧‧Protective film

6‧‧‧Protective film

7‧‧‧ peeling unit

8‧‧‧ peeling unit

9‧‧‧feeding area

10‧‧‧Drawing area

11‧‧‧Sensor in the feed zone

12‧‧‧Feed roller

13‧‧‧Additional air nozzle

14‧‧‧Vacuum aspirator

14a‧‧‧Upper vacuum aspirator

14b‧‧‧Under vacuum aspirator

15‧‧‧Rolling wheel

16‧‧‧ knurling wheel

17‧‧‧Prepared air nozzle

18‧‧‧Prepared air nozzle

19‧‧‧Fins

20‧‧‧Fins

21‧‧‧Main air nozzle

22‧‧‧Main air nozzle

23‧‧‧Upper discharge roller

24‧‧‧Under discharge roller

25‧‧‧Roller

26‧‧‧Roller

27‧‧‧Additional air nozzle slot

28‧‧‧Additional air nozzle slot

29‧‧‧ receiving container

30‧‧‧Sucking area

31‧‧‧Separated ends

1 is a schematic cross-sectional view of a protective film peeling device and a copper clad printed circuit board substrate located in a feeding zone; FIG. 2 is a top plan view of the peeling device; and FIG. 3 is a peeling device feed zone when detecting a leading edge of the printed circuit board substrate Figure 4 is a schematic cross-sectional view of the stripping device when the knurling wheel is placed on the leading edge of the printed circuit board substrate; Figure 5 is a schematic cross-sectional view of the stripping device when the protective film is placed on the tip of the fin Figure 6 is a schematic cross-sectional view of the peeling device when the leading edge of the protective film reaches the end of the two fins; Figure 7 is a schematic cross-sectional view of the peeling device when the supplementary air nozzle is activated; Figure 8 is a protective film peeling device and a copper clad printed circuit board The cross-sectional view of the substrate when the lower protective film is separated from the surface of the drum and the upper drum continues to transport the protective film; FIG. 9 is the protective film peeling device and the copper-clad printed circuit board substrate are stored in the storage container and the front edge of the upper protective film. FIG. 10 is a schematic cross-sectional view of the upper roller and the lower roller in contact with each other; FIG. 10 is a protective film peeling device and a copper-clad printed circuit board substrate. The upper protective film is removed by being vacuumed by the upper vacuum aspirator to the lower vacuum aspirator. FIG. 11 is a schematic cross-sectional view showing the protective film peeling device and the copper-clad printed circuit board substrate. After the lower roller rotates the upper protective film away from the upper roller and the lower roller by about 90°, the protective film is released. FIG. 12 is a schematic cross-sectional view showing the protective film peeling device and the copper clad printed circuit board substrate when the upper protective film is stored in the storage container.

1 is a schematic cross-sectional view of a stripping device 1 and a printed circuit board substrate 2 located in a feed zone. The printed circuit board substrate 2 is made of, for example, FR4, 5 polyimine (PI), liquid crystal polymer (LCP), and has copper having a thickness of 9 μm to 35 μm on both sides.

The stripping device has at least one stripping unit 7, 8 for separating the protective film 5. According to Fig. 1, the two cylindrical rollers 25, 26 are spaced apart in the vertical direction. However, the invention is not limited to the implementation of the stripping units 7, 8 as cylindrical, but rather includes There are geometric shapes such as rectangles, triangles, ellipses, or the like.

The protective film 5 is provided on the glossing polymer layer 3 or on the lower photopolymer layer 4. However, a protective film 5 may be provided on both the upper and lower photopolymer layers 3 and 4. The protective film 5 is an extremely thin metal piece or a plastic piece. The protective film is preferably composed of, for example, a polyester (PET film) having a thickness of about 12 μm, 15 μm or 21 μm.

According to Fig. 1, the stripping device 1 has, in front of the stripping units 7, 8, for example a feed zone 9 comprising a transport station or a roller/belt conveyor. The printed circuit board substrate 2 to be processed is fed into the stripping units 7, 8 via the feed zone 9. According to a preferred embodiment, the feed zone 9 is provided with a sensor 11 for detecting the starting point of the plate body and a feed roller 12 for feeding the plate body to the stripping units 7, 8.

The feed zone 9 is further provided with at least one supplementary air nozzle 13 which loads the (air) gas stream for the at least one stripping unit 7, 8. The supplemental air nozzle 13 is preferably located between the feed roller 12 and the stripping units 7, 8.

The peeling units 7, 8 are cylindrical and spaced apart in the vertical direction. This vertical direction spacing allows the printed circuit board substrate 2 to be processed to pass between the upper peeling unit 7 and the lower peeling unit 8.

The stripping unit 7, 8 or the drums 25, 26 have a vacuum aspirator 14 or an outlet for the vacuum aspirator 14 in its outer surface area. Thereby, a vacuum flow can be formed in at least one section of the surface of the stripping units 7, 8, and thereby the protective film 5 can be sucked or held.

At least one upper knurling wheel 15 and/or at least one lower knurling wheel 16 is provided in the region of the drums 25, 26 having the smallest vertical spacing. The printed circuit board substrate 2 is advanced inside the peeling units 7, 8 by the knurling wheels 15, 16. Further, a clear pressure is applied to the printed circuit board 2 and the protective film 5 by the knurling wheels 15, 16. Thereby, the edge of the protective film 5 is opened to obtain a partial separation effect.

At least one preliminary air nozzle 17, 18 is provided behind the knurling wheels 15, 16 in the horizontal direction, which provides support for the protective membrane 5 to be initially separated from the photopolymer layer (3, 4) by the knurling wheels 15, 16. Preferably, a preliminary air nozzle 17 is provided on the top surface side of the printed circuit board 2 to be processed, and a preliminary air nozzle 18 is provided on the bottom surface side thereof.

At least one fin 19, 20 is disposed behind the preliminary air nozzles 17, 18, and the fin is interposed between the protective film 5 and the printed circuit board substrate 2 with a separation edge to separate the protective film 5 from the printed circuit board substrate 2. Such fins 19, 20 are also referred to as transport sheets. Preferably, the fins 19 are provided on the top surface side of the printed circuit board substrate 2, and the fins 20 are provided on the bottom surface side thereof. The fins 19, 20 have straight separating edges which are interposed between the photopolymer layers 3, 4 of the printed circuit board substrate 2 and the protective film 5 over the entire width.

According to another preferred embodiment, the fins 19, 20 are constructed such that only the tip is initially embedded between the protective film 5 and the printed circuit board substrate 2, and the rear fins 19, 20 are between the printed circuit board substrate 2 and the protective film 5. The embedding width gradually becomes larger. This has the advantage of being able to operate at a higher speed, thereby accelerating the separation of the protective film 5 from the printed circuit board substrate 2.

The fins 19, 20 peel off the protective film 5 from the printed circuit board substrate 2, wherein the protective film 5 continues to advance along the surface of the fin.

At least one main air nozzle 21, 22 is provided behind the fins 19, 20. Preferably, a main air nozzle 21 is provided on the top surface side of the printed circuit board substrate 2, and a main air nozzle 22 is provided on the bottom surface side thereof. The air flow of the main air nozzles 21, 22 lifts the peeled protective film 5 onto the fins 19, 20 so that the fin can perform the separation process.

Behind the main air nozzles 21, 22 are provided at least one discharge roller 23, 24 which transports the processed printed circuit board substrate 2 away from the stripping units 7, 8 towards the exit zone 10.

2 is a schematic cross-sectional view of the feed zone 9 of the stripping device 1 of the present invention. The arrangement of the supplementary air nozzles 13 in the area of the stripping units 7, 8 can be clearly seen from the top view of the figure. The supplemental air nozzles 13 are here preferably provided in their own supplementary air nozzle slots 27, 28 which are situated in the surface area of the rollers 25, 26 of the stripping units 7, 8.

Starting from the feed zone 9, a sensor 11, a feed roller 12, a supplemental air nozzle 13, a vacuum aspirator 14, fins 19, 20, preliminary air nozzles 17, 18, and a main air nozzle 21 are sequentially disposed in the machine direction. 22 and the discharge rollers 23, 24.

Figure 3 is a schematic cross-sectional view of the stripping device feed zone when the leading edge of the printed circuit board substrate is detected. The printed circuit board substrate 2 is detected by the feed sensor 11. The signal from sensor 11 activates feed rolls 12 that synchronize the printed circuit board substrate.

Fig. 4 shows the peeling device 1 when the knurling wheels 15, 16 are placed on the front edge of the printed circuit board substrate 2. The edge of the protective film 5 is opened by the pressure of the knurling wheels 15, 16 to obtain the effect of the preliminary separation of the protective film 5 from the printed circuit board substrate 2. This separation procedure is supported by the air flow of the preliminary air nozzles 17, 18.

FIG. 5 shows the point in time at which the protective film 5 is placed on the fin tips 19, 20. The protective film 5 is lifted up to the fin tip by the air flow of the main air nozzles 21, 22 before the film edge of the protective film 5 reaches the fin tip.

According to FIG. 6, the protective film 5 is exposed from the printed circuit board substrate 2 in the suction region 30. The protective film 5 is peeled off by the printed circuit board 2 by the fins 19 by the advancement of the printed circuit board 2. The separated end 31 is adsorbed to the outer circumference of the drum 25 due to the Coanda effect. When the separated end 31 reaches the vacuum aspirator 14, the vacuum aspirator activates and assumes the task of continuing to guide and hold the protective film 5 along the drum 25. The point is that the vacuum aspirator 14 does not generate suction in the suction zone 30, but the separated end 31 is only transparent. The Coanda effect is attached to the outer circumference of the drum 25. Thereby, the protective films 5, 6 can be peeled off even if the printed circuit board is thinner, and conventional devices are not yet available.

According to prior embodiments of the prior art, there is always the disadvantage that the spatial arrangement of the rollers 25, 26 relative to the fins 19, 20 is such that the separated end 31 is remote from the vacuum aspirator 14 so that the vacuum flow cannot hold the protective film 5. The reason why the vacuum flow cannot be started earlier is that this causes the thinner printed circuit board to be sucked together.

The present invention solves the above problems by providing a supplemental air nozzle 13 in the feed zone 9. The makeup air nozzle 13 loads the drum 25 with a tangential air flow, thereby inducing a Coanda effect in the suction zone 30 and adsorbing the separated end 31 of the protective film 5 to the periphery of the drum.

After the replenishing air nozzle 13 is activated, the protective film 5 is sucked along the rollers 25, 26 and follows its contour until the separated end 31 of the protective film is intercepted by the vacuum of the vacuum aspirator 14. The higher the air flow rate, the better the effect. Under the optimum conditions, the protective film 5 is attached to the rolls 25, 26 almost 360°.

The effect produced by the supplemental air nozzle 13 is also known as the Coanda effect or the "Keanda flow". The Coanda flow has an unusual ability to flow along the projecting rollers 25, 26 without falling off. Therefore, the air jet of the supplemental air nozzle 13 flows along the rollers 25, 26 and the protective film 5 is attracted to the drum during the separation process. The advantage is mainly that the thinner printed circuit board substrate 2 can also be processed, since the Coanda flow has already retained the protective film 5 before the actual separation process. When separated from the printed circuit board substrate 2, the protective film 5 adheres to the periphery of the rollers 25, 26 and is peeled off by the fins 19, 20.

FIG. 7 shows that the front region of the protective film 5 is peeled off from the printed circuit board substrate 2 and the protective film 5 is attracted to the surfaces of the rollers 25, 26. Once the protective film 5 is attached to the surface of the rollers 25, 26, the vacuum aspirator 14 is activated and the makeup air nozzle 13 is deactivated. borrow This transfers the protective film 5 from the generated supplemental air nozzle flow to the vacuum flow.

Figure 8 shows the separated protective films 5, 6 carried along the surface of the associated rollers 25, 26. After the vacuum aspirator 14 is activated, the upper protective film 5 is held on the surface of the drum during the rotational movement of the drum 25. According to FIG. 8, the lower vacuum aspirator 14 is deactivated to cause the lower protective film 6 to be separated from the surface of the drum 26.

FIG. 9 shows that the lower protective film 6 is stored in the storage container 29. The leading edge of the upper protective film 5 reaches the contact position of the upper roller 25 and the lower roller 26, and is held by the upper vacuum aspirator 14a. The two rollers 25, 26 are positioned until the upper vacuum suction outlet 14a is opposed to the lower vacuum suction outlet 14b.

FIG. 10 shows the point in time at which the upper protective film 5 is transferred from the upper drum 25 to the lower drum 26. This is achieved by switching from the upper vacuum aspirator 14a to the lower vacuum aspirator 14b. For this purpose, the upper vacuum aspirator 14a is deactivated and the lower vacuum aspirator 14b is activated.

According to a preferred embodiment, the jet can be further passed through to support separation of the upper protective film 5 from the drum 25.

The lower vacuum aspirator 14b is activated only for the short-term rotational movement of the lower drum 26. It only lasts until the upper protective film 5 is located in the area of the receiving container 29 and is stored there.

Referring specifically to Figure 11, this figure primarily illustrates the separation of the vacuum aspirator 14b and the protective membrane 5 from the lower drum 26 when deactivated.

FIG. 12 shows that the upper protective film 5 is finally stored in the receiving container 29. At this time, there is no material in the peeling device 1, and the next printed circuit board substrate 2 can be processed.

In summary, the flow along the surfaces of the drums 25, 26 is generated by providing additional supplemental air nozzles 13 in the feed zone 9 of the stripping units 7, 8, which are early cut The protective film 5 is housed, wherein the protective films 5, 6 are separated from the printed circuit board substrate 2 by the rotation of the rollers 25, 26. The supplemental air nozzles 13 are preferably located within the supplemental air nozzle slots 27, 28 of the drum.

1‧‧‧ peeling device

2‧‧‧Printed circuit board substrate

3‧‧‧Photopolymer layer

4‧‧‧Photopolymer layer

5‧‧‧Protective film

6‧‧‧Protective film

7‧‧‧ peeling unit

8‧‧‧ peeling unit

9‧‧‧feeding area

10‧‧‧Drawing area

11‧‧‧Sensor in the feed zone

12‧‧‧Feed roller

13‧‧‧Additional air nozzle

14‧‧‧Vacuum aspirator

15‧‧‧Rolling wheel

16‧‧‧ knurling wheel

17‧‧‧Prepared air nozzle

18‧‧‧Prepared air nozzle

19‧‧‧Fins

20‧‧‧Fins

21‧‧‧Main air nozzle

22‧‧‧Main air nozzle

23‧‧‧ discharge roller

24‧‧‧ discharge roller

25‧‧‧Roller

26‧‧‧Roller

Claims (10)

A device for stripping at least one protective film from a printed circuit board, the printed circuit board being fed into a roll gap of a peeling unit (7, 8) in which wedge-shaped fins (19, 20) are embedded The printed circuit board (2) is separated from the protective film (5, 6) and the protective film (5, 6) is separated from the printed circuit board (2), wherein the separated protective film (5, 6) It is carried by a driven rotating drum (25, 26), characterized in that at least one supplementary air nozzle (13) is arranged in front of the fin (19, 20), and the supplementary air nozzle is tangentially directed to the drum A flow of air is applied around the periphery of (25, 26) such that a portion of the protective film (5, 6) that has detached from the printed circuit board (2) is attached to the periphery of the roller (25, 26). The apparatus of claim 1, wherein the at least one supplemental air nozzle (13) is disposed in the at least one radially recessed slot (27, 28) of the roller (25, 26). The device of claim 1 or 2, wherein the drum (25, 26) has at least one vacuum aspirator (14). The device of claim 1 or 2, wherein at least one sensor (11) is provided in the feeding zone (9) of the stripping unit (7, 8), and the stripping device (1) is activated by the sensor . The apparatus of claim 1 or 2, wherein the apparatus (1) has two rotating drums (25, 26) forming a roll gap through which the printed circuit board (2) can pass to complete the printed circuit board (2) Separation procedures of the protective film (5, 6) on the top and bottom surfaces. The apparatus of claim 1 or 2, wherein at least one preliminary air nozzle (17, 18) and a main air nozzle (21, 22) are provided in the stripping unit (7, 8). A device according to claim 1 or 2, wherein the drum (25, 26) has at least one discharge nozzle for removing the protective film (5, 6) from the surface of the drum (25, 26). A method of stripping at least one protective film from a printed circuit board, the printed circuit board being Feeding into the nip of the stripping unit (7, 8), in which the wedge-shaped fins (19, 20) are embedded between the printed circuit board (2) and the protective film (5, 6) and The protective film (5, 6) is separated from the printed circuit board (2), wherein the separated protective film (5, 6) is carried by the driven rotating drum (25, 26) and is characterized by the following Step: placing at least one knurling wheel (15, 16) onto the printed circuit board (2) and running over the protective film (5, 6); applying air flow to the at least one preliminary air nozzle (17, 18) The edge of the protective film (5, 6); the edge of the protective film (5, 6) is lifted onto the wedge-shaped fin (19, 20) by at least one main air nozzle (21, 22); toward the fin Advancing the printed circuit board to separate the protective film (5, 6) from the printed circuit board (2); starting a supplemental air nozzle (13) that is rotated while the roller (25, 26) is rotating The tangent of the rollers (25, 26) creates a flow of air such that the separated ends of the protective film are attached to the periphery of the drum. The method of claim 8, wherein the separated protective film (5, 6) is held by the vacuum aspirator (14a, 14b) on the surface of the roller (25, 26) and carried by it. The method of claim 8 or 9, wherein the protective film (5) of the upper drum (25) is fed into the contact area of the vacuum aspirator (14b) below the lower drum (26); the upper vacuum aspirator is deactivated (14a) and actuating the lower vacuum aspirator (14b) to transfer the protective film (5) to the lower drum (26); the lower drum (26) is rotated toward the receiving container (29); The lower vacuum aspirator (14b) is deactivated at the height of the receiving container so that the protective film (5, 6) is detached from the surface of the drum (26) and falls into the receiving container (29).